517 research outputs found
Deleterious Effects of Cold Air Inhalation on Coronary Physiological Indices in Patients With Obstructive Coronary Artery Disease
Background
Cold air inhalation during exercise increases cardiac mortality, but the pathophysiology is unclear. During cold and exercise, dualâsensor intracoronary wires measured coronary microvascular resistance (MVR) and blood flow velocity (CBF), and cardiac magnetic resonance measured subendocardial perfusion.
Methods and Results
Fortyâtwo patients (62±9 years) undergoing cardiac catheterization, 32 with obstructive coronary stenoses and 10 without, performed either (1) 5 minutes of cold air inhalation (5°F) or (2) two 5âminute supineâcycling periods: 1 at room temperature and 1 during cold air inhalation (5°F) (randomized order). We compared rest and peak stress MVR, CBF, and subendocardial perfusion measurements. In patients with unobstructed coronary arteries (n=10), cold air inhalation at rest decreased MVR by 6% (P=0.41), increasing CBF by 20% (P<0.01). However, in patients with obstructive stenoses (n=10), cold air inhalation at rest increased MVR by 17% (P<0.01), reducing CBF by 3% (P=0.85). Consequently, in patients with obstructive stenoses undergoing the cardiac magnetic resonance protocol (n=10), cold air inhalation reduced subendocardial perfusion (P<0.05). Only patients with obstructive stenoses performed this protocol (n=12). Cycling at room temperature decreased MVR by 29% (P<0.001) and increased CBF by 61% (P<0.001). However, cold air inhalation during cycling blunted these adaptations in MVR (P=0.12) and CBF (P<0.05), an effect attributable to defective early diastolic CBF acceleration (P<0.05) and associated with greater STâsegment depression (P<0.05).
Conclusions
In patients with obstructive coronary stenoses, cold air inhalation causes deleterious changes in MVR and CBF. These diminish or abolish the normal adaptations during exertion that ordinarily match myocardial blood supply to demand
Independent Origins of Cultivated Coconut (Cocos nucifera L.) in the Old World Tropics
As a portable source of food, water, fuel, and construction materials, the coconut (Cocos nucifera L.) played a fundamental role in human migrations and the development of civilization across the humid tropics. Here we investigated the coconut's domestication history and its population genetic structure as it relates to human dispersal patterns. A sample of 1,322 coconut accessions, representing the geographical and phenotypic diversity of the species, was examined using ten microsatellite loci. Bayesian analyses reveal two highly genetically differentiated subpopulations that correspond to the Pacific and Indo-Atlantic oceanic basins. This pattern suggests independent origins of coconut cultivation in these two world regions, with persistent population structure on a global scale despite long-term human cultivation and dispersal. Pacific coconuts show additional genetic substructure corresponding to phenotypic and geographical subgroups; moreover, the traits that are most clearly associated with selection under human cultivation (dwarf habit, self-pollination, and âniu vaiâ fruit morphology) arose only in the Pacific. Coconuts that show evidence of genetic admixture between the Pacific and Indo-Atlantic groups occur primarily in the southwestern Indian Ocean. This pattern is consistent with human introductions of Pacific coconuts along the ancient Austronesian trade route connecting Madagascar to Southeast Asia. Admixture in coastal east Africa may also reflect later historic Arab trading along the Indian Ocean coastline. We propose two geographical origins of coconut cultivation: island Southeast Asia and southern margins of the Indian subcontinent
Measurement of B(/\c->pKpi)
The /\c->pKpi yield has been measured in a sample of two-jet continuum events
containing a both an anticharm tag (Dbar) as well as an antiproton (e+e- ->
Dbar pbar X), with the antiproton in the hemisphere opposite the Dbar. Under
the hypothesis that such selection criteria tag e+e- -> Dbar pbar (/\c) X
events, the /\c->pkpi branching fraction can be determined by measuring the
pkpi yield in the same hemisphere as the antiprotons in our Dbar pbar X sample.
Combining our results from three independent types of anticharm tags, we obtain
B(/\c->pKpi)=(5.0+/-0.5+/-1.2)
To treat or not to treat: comparison of different criteria used to determine whether weight loss is to be recommended
Background: Excess body fat is a major risk factor for disease primarily due to its endocrine
activity. In recent years several criteria have been introduced to evaluate this factor. Nevertheless,
treatment need is currently assessed only on the basis of an individual's Body Mass Index (BMI),
calculated as body weight (in kg) divided by height in m2. The aim of our study was to determine
whether application of the BMI, compared to adiposity-based criteria, results in underestimation of
the number of subjects needing lifestyle intervention.
Methods: We compared treatment need based on BMI classification with four adiposity-based
criteria: percentage body fat (%BF), considered both alone and in relation to metabolic syndrome
risk (MS), waist circumference (WC), as an index of abdominal fat, and Body Fat Mass Index (BFMI,
calculated as fat mass in kg divided by height in m2) in 63 volunteers (23 men and 40 women, aged
20 â 65 years).
Results: According to the classification based on BMI, 6.3% of subjects were underweight, 52.4%
were normal weight, 30.2% were overweight, and 11.1% were obese. Agreement between the BMI
categories and the other classification criteria categories varied; the most notable discrepancy
emerged in the underweight and overweight categories. BMI compared to almost all of the other
adiposity-based criteria, identified a lower percentage of subjects for whom treatment would be
recommended. In particular, the proportion of subjects for whom clinicians would strongly
recommend weight loss on the basis of their BMI (11.1%) was significantly lower than those
identified according to WC (25.4%, p = 0.004), %BF (28.6%, p = 0.003), and MS (33.9%, p = 0.002).
Conclusion: The use of the BMI alone, as opposed to an assessment based on body composition,
to identify individuals needing lifestyle intervention may lead to unfortunate misclassifications.
Population-specific data on the relationships between body composition, morbidity, and mortality
are needed to improve the diagnosis and treatment of at-risk individual
Relation of DNA Methylation of 5âČ-CpG Island of ACSL3 to Transplacental Exposure to Airborne Polycyclic Aromatic Hydrocarbons and Childhood Asthma
In a longitudinal cohort of âŒ700 children in New York City, the prevalence of asthma (>25%) is among the highest in the US. This high risk may in part be caused by transplacental exposure to traffic-related polycyclic aromatic hydrocarbons (PAHs) but biomarkers informative of PAH-asthma relationships is lacking. We here hypothesized that epigenetic marks associated with transplacental PAH exposure and/or childhood asthma risk could be identified in fetal tissues. Mothers completed personal prenatal air monitoring for PAH exposure determination. Methylation sensitive restriction fingerprinting was used to analyze umbilical cord white blood cell (UCWBC) DNA of 20 cohort children. Over 30 DNA sequences were identified whose methylation status was dependent on the level of maternal PAH exposure. Six sequences were found to be homologous to known genes having one or more 5âČ-CpG island(s) (5âČ-CGI). Of these, acyl-CoA synthetase long-chain family member 3 (ACSL3) exhibited the highest concordance between the extent of methylation of its 5âČ-CGI in UCWBCs and the level of gene expression in matched fetal placental tissues in the initial 20 cohort children. ACSL3 was therefore chosen for further investigation in a larger sample of 56 cohort children. Methylation of the ACSL3 5âČ-CGI was found to be significantly associated with maternal airborne PAH exposure exceeding 2.41 ng/m3 (ORâ=â13.8; p<0.001; sensitivityâ=â75%; specificityâ=â82%) and with a parental report of asthma symptoms in children prior to age 5 (ORâ=â3.9; p<0.05). Thus, if validated, methylated ACSL3 5âČCGI in UCWBC DNA may be a surrogate endpoint for transplacental PAH exposure and/or a potential biomarker for environmentally-related asthma. This exploratory report provides a new blueprint for the discovery of epigenetic biomarkers relevant to other exposure assessments and/or investigations of exposure-disease relationships in birth cohorts. The results support the emerging theory of early origins of later life disease development
Azimuthal anisotropy of charged particles at high transverse momenta in PbPb collisions at sqrt(s[NN]) = 2.76 TeV
The azimuthal anisotropy of charged particles in PbPb collisions at
nucleon-nucleon center-of-mass energy of 2.76 TeV is measured with the CMS
detector at the LHC over an extended transverse momentum (pt) range up to
approximately 60 GeV. The data cover both the low-pt region associated with
hydrodynamic flow phenomena and the high-pt region where the anisotropies may
reflect the path-length dependence of parton energy loss in the created medium.
The anisotropy parameter (v2) of the particles is extracted by correlating
charged tracks with respect to the event-plane reconstructed by using the
energy deposited in forward-angle calorimeters. For the six bins of collision
centrality studied, spanning the range of 0-60% most-central events, the
observed v2 values are found to first increase with pt, reaching a maximum
around pt = 3 GeV, and then to gradually decrease to almost zero, with the
decline persisting up to at least pt = 40 GeV over the full centrality range
measured.Comment: Replaced with published version. Added journal reference and DO
Search for new physics with same-sign isolated dilepton events with jets and missing transverse energy
A search for new physics is performed in events with two same-sign isolated
leptons, hadronic jets, and missing transverse energy in the final state. The
analysis is based on a data sample corresponding to an integrated luminosity of
4.98 inverse femtobarns produced in pp collisions at a center-of-mass energy of
7 TeV collected by the CMS experiment at the LHC. This constitutes a factor of
140 increase in integrated luminosity over previously published results. The
observed yields agree with the standard model predictions and thus no evidence
for new physics is found. The observations are used to set upper limits on
possible new physics contributions and to constrain supersymmetric models. To
facilitate the interpretation of the data in a broader range of new physics
scenarios, information on the event selection, detector response, and
efficiencies is provided.Comment: Published in Physical Review Letter
Compressed representation of a partially defined integer function over multiple arguments
In OLAP (OnLine Analitical Processing) data are analysed in an n-dimensional cube. The cube may be represented as a partially defined function over n arguments. Considering that often the function is not defined everywhere, we ask: is there a known way of representing the function or the points in which it is defined, in a more compact manner than the trivial one
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